There is no single best way to store a seed phrase. Every choice, guided by your personal threat model and recovery priorities, involves tradeoffs.
Misjudging these tradeoffs can result in the irreversible loss of your Bitcoin.
This guide explores storage methods, locations where to store a seed phrase, and best practices tailored to different custody models. Use it to build a strategy that balances protection and practicality.
Seed Phrases and Their Role in Bitcoin Security
Seed phrases are the cryptographic backups for Bitcoin wallets. Compromise grants full access to funds, making durability and privacy non-negotiable.
Threats to your recovery phrase are plenty, from physical risks like fire and water damage to digital breaches and coercion. Even your own errors, whether through forgetfulness, mismanagement, or exposure, pose a significant risk.
Proactive planning is essential to guard against these dangers, ensuring your backups stay secure and recoverable when needed.
Seed Phrase Storage Methods
Paper Wallets
Paper remains one of the most accessible seed phrase storage methods, as it allows users to write or print their seed words using basic tools.
However, this simplicity comes with inherent vulnerabilities.
Physical damage from tearing, fire, or water exposure can render paper backups unusable, while ink fading over time further reduces reliability. Even lamination only partially addresses these weaknesses, introducing additional steps and costs.
If printed, risks extend to digital exposure. Printers often retain data in memory, and connected devices may compromise security if not air-gapped or wiped after use.
These limitations make paper a weak long-term solution for serious Bitcoin holders.
Pros
Cons
Metal Backups
Metal backups are created by engraving, stamping, or assembling seed words using metal tiles with individual letters. Methods like cassettes or plates offer inherent durability, but differ in convenience, resistance to damage, and tamper-evident features.
Material choice also matters. Stainless steel and titanium maintain structural integrity under harsh conditions, ensuring legibility for decades. Other metals may degrade faster, limiting their suitability for long-term storage.
Some metal backup models include tamper-evident design features. Others may require additional safeguards like tamper-evident bags to signal unauthorized access.
Factory-made units are available at various price points. DIY allows for cost reduction, but demands additional time and planning to ensure durability and readability.
Metal backups are widely adopted by Bitcoiners, and represent a popular choice for long-term storage.
Pros
Cons
Digital Solutions
Digital storage involves saving seed phrases as files.
These can be text files (e.g., Notepad, Excel) or digital images (e.g., screenshots, photos of physical backups). Basic digital storage uses USB drives, hard drives, or cloud services (Google Drive, Dropbox).
While digital storage is a convenient option, it carries risks: exposure to malware, phishing, and device compromise. Encryption, or air-gapped devices, can mitigate the risks, but add complexity in key management and technical setup.
Bitcoiners typically avoid exposing mnemonic phrases to digital environments. The only exception is when using trusted hardware wallets that isolate private keys.
Pros
Cons
Brain Wallets
Brain wallets involve memorizing a seed phrase instead of storing it physically or digitally.
Memorization can be useful for emergency scenarios, when physical backups are unavailable.
Some approaches aim to reduce cognitive load, such as Border Wallets. However, even these still rely entirely on human memory.
Human memory is highly susceptible to stress, time pressure, or adverse conditions. These factors increase the likelihood of forgetting or mis-recalling seed words. Unforeseen death or sudden incapacitation may result in irreversible loss.
Brain wallets shift the burden to human reliability, which remains unpredictable under long-term scenarios.
Pros
Cons
Places to Store a Seed Phrase
Home Storage
Storing seed phrase backups inside one’s residence is a common choice, but carries distinct risks.
Insecure locations (e.g., open drawers, shelves) increase the chance of unauthorized discovery. However, even “secure” methods like safes or fireproof containers may fail to protect against pests, decay, or unauthorized access by trusted individuals.
Additionally, co-locating backups with hardware wallets (e.g., storing both in the same safe) raises the risk of simultaneous loss due to theft, fire, or water exposure.
Pros
Cons
On-Property Storage
Storing backups on one’s property (e.g., buried in a garden, locked shed, detached garage) is another common solution.
While it provides segregation from hardware wallets, it introduces unique risks. Environmental hazards like weather, pests, or temperature fluctuations can degrade backups. Even secure methods may fail if the location is forgotten over time.
Pros
Cons
Bank Safe Deposit Box
Renting a secure, off-site container at a financial institution or private vault service provides institutional-grade security for recovery phrase storage.
Access is limited to business hours and may be blocked during holidays, emergencies, or if legal documentation (e.g., death of the renter, account freezes) restricts retrieval. Breaches or insider theft could compromise backups, and long-term costs from annual fees can accumulate.
Pros
Cons
Trusted Contact’s Home
Storing a backup at a friend’s or family member’s residence provides off-site security without recurring fees.
Insecure locations (e.g., open drawers, shelves) risk accidental discovery or loss if the contact moves, forgets the location, or denies access. Secure storage (e.g., locked safe, tamper-evident packaging) reduces exposure, but still depends on the contact’s cooperation and stability.
Pros
Cons
Seed Phrase Storage by Custody Model
This guide focuses on non-custodial methods, where you maintain full control over your seed phrase. But custodial solutions exist, where a third-party service holds and manages it on your behalf. Additionally, collaborative custody models allow you to share its control and management with a third party.
Single-Sig
In this setup, a single seed phrase grants full control over your funds.
Your backup is the sole point of failure. If it is stolen, lost, or damaged, your coins become compromised or inaccessible. And there are no recovery options available, such as customer service or external help.
Your menmonic phrase must remain confidential, as exposure would result in total loss. Furthermore, your backup methods and locations should also remain confidential to minimize the risk of theft or coercion.
Given the risks associated with single-sig wallets, you should carefully consider your storage strategy. Your goal is to ensure that your backup remains secure, yet accessible when you need it. This requires a balance between protection and practicality.
- Use one durable, tamper-evident backup (e.g., metal plate) in a secure location (e.g., home safe) that is separate from your wallet.
- Consider an optional second durable, tamper-evident backup (e.g., metal plate), stored in a different secure location (e.g., buried on property).
- Avoid third-party facilities (e.g., bank safe deposit boxes) unless addressing specific coercion risks (e.g., forced access).
Note: Some bitcoiners say splitting the seed phrase can add an extra layer of security, but it also increases the risk of loss and brute force attacks. This approach is not recommended for most users.
Single-Sig + Passphrase
This setup adds an extra layer of security, requiring not only a seed phrase, but also a passphrase to get full control over your funds.
Both the seed sentence and passphrase are required to access your funds. If either is stolen, lost, or damaged, your funds will become inaccessible. As with Single-Sig, there are no recovery options available.
It’s also essential to store both secrets securely, while also ensuring they are not stored together, which would negate the security benefits of the passphrase.
To mitigate these risks, it’s essential to develop a secure storage strategy for both your recovery phrase and passphrase.
- Create separate, durable, tamper-evident backups for your seed phrase and passphrase (e.g., two metal plates).
- Store the seed phrase in a secure location (e.g., home safe) that is separate from your wallet, and store the passphrase in a distinct and unlinked secure location (e.g., bank safe deposit box, trusted contact home).
Single-Sig + Shamir’s Secret Sharing
This setup combines the security of Shamir’s Secret Sharing (SSS) with the simplicity of a single-sig wallet. SSS divides your seed phrase into multiple shares, requiring a specific number of shares to be combined to recover it.
One of the key benefits of SSS is that it can tolerate the loss or damage of some shares. In the case of a 2-of-3 setup, if one share is lost or damaged, the remaining two shares can still be used to recover your mnemonic phrase.
Additionally, SSS makes it more difficult for an attacker to gain access to your funds, as they would need to compromise multiple shares.
It’s also worth noting that individual shares are less sensitive than the original seed phrase, as they do not contain enough information to recover it on their own.
However, for SSS to be effective, each share must be stored in a separate location.
By implementing a well-designed storage strategy, you can maximize the security benefits of SSS and protect your assets from potential threats.
- Use separate, durable, tamper-evident backups (e.g., metal plates) for each share.
- Distribute the backups to geographically separate locations (e.g., home safe, trusted contact, bank box).
Multi-Sig
In a Multi-Sig setup, multiple seed phrases are required to control your funds, using an M-of-N scheme.
One of the key benefits of Multi-Sig is that it can tolerate the loss or damage of some seed phrases. For example, in a 2-of-3 setup, you can still recover your funds even if one of the mnemonic phrases is lost or damaged.
Additionally, an attacker would need to compromise multiple backups to gain access to your funds, making it a more secure option.
However, recovering your funds requires not only the seed phrases, but also the wallet configuration information. So, it’s still crucial to store it securely to be able to reconstruct your wallet.
Plus, it’s essential to store the seed phrases separately, as storing them together would negate the model’s security benefits.
To fully leverage the security benefits of Multi-Sig, you need to develop a storage strategy that accounts for the unique requirements of this setup.
- Use separate, durable, tamper-evident backups (e.g., metal plates) for each seed phrase.
- Distribute the backups to geographically separate locations (e.g., home safe, trusted contact, bank box).
- Store the wallet configuration information digitally (e.g., encrypted password manager) and physically (e.g., printed sheet) in distinct, unlinked locations.
Note: Some bitcoiners recommend including a configuration copy with each backup. While this approach provides an additional layer of redundancy, it exposes data like your balance and transactions. It may also put your other backups at risk.
Conclusion
So, what is the best way to store a seed phrase? The answer is not a single solution, but rather a thoughtful and strategic approach that takes into account your individual needs and circumstances.
The goal is to manage risk, not eliminate it.
Each storage strategy balances durability, tamper resistance, and accessibility differently. And, as your circumstances change, such as relocating or emerging new attack vectors, it’s crucial to reassess your backups and adapt your strategy accordingly.
Your custody model determines the storage methods and locations that are best for you. Because each model has unique requirements that impact the security and accessibility of your funds.
However, regardless of the custody model, one thing remains constant: the need for durable and tamper-evident backups. Seed Keys offer solutions for long-term physical recovery phrase storage, designed to secure your financial future.